Control arrangements for fluid pressure actuated pistons



July 5, 1955 ZQLLER 2,712,302

CONTROL ARRANGEMENTS FOR FLUID PRESSURE ACTUATED PISTONS Filed Sept. 15, 1951 i" a EL: 30 36 45 3 15 I 26 2 7 I 7 S49 1 a '21 2910 4 4']; 39 42 12 1 HANS ZOLLER 3 I MIH/IOR ms ATTORNEYS United StatesPatCn CONTROL ARRANGEMENTS FOR FLUID rnnssunn ACTUATED PISTONS V 'Hans'Ziiller, Laubenlleim on Rhine, Germany Application September 15, 1951 Serial No. 146,821 Claims priority, application Germany September 19, 1950 s Claims. 01. 121-157 I This invention. relates to control: arrangements for fluid pressure actuated pistons and is concerned with installa- 2,712,302 Patented July 5, 1955 1 piston head. 4a of the piston 4, through a conduit 10' into a cylinder 14 and moves the working. piston 15 to the right in its cylinder 14. Simultaneously, the main air passing tlnon'ghv valve 2 to a conduit. 2 3v reaches a gasket 21 within another control cylinder 21a containing slide valve. elements. Air or. a spring 22, or both. to?

tions in which a piston or pistons is' or are operated by a horrid in one or more.- working. cylinders. The invention enables the speed of a working piston to be-very accurately and; infinitely varied in either" direca compressed-pressure medium for example air, gas or tion from a minimum to a maximum, the actual control being effected by the working medium itself and without the aid of any extraneous source. of power such, for example, as electricity.

Accordingto the. present inventiomv in a control arrangement. for. a fluid. pressure actuated working. piston, on both its power stroke and. on its return stroke, the piston serves to actuate or control means for alternately applying fluid pressure:to,. or removing such pressure-from, a. member which -senves to open and close an inlet for a fluid pressure. medium to the cylinder of the working piston and to close and. open respectively an ontlet for said pressuremedium said member itself being actuated by thepressuremedium.

I In particular arrangements according to. .theinvention,

the member referred. to is a piston arranged to. reciprocate in a cylinder and in conjunction withapertured partitions insaid cylinder and inlet and outlet ports constitutes. a

first slide valve disposed between a main check or control valve connected to a sourceof fluid. pressure'andi the cylinder of the working piston. In such arrangements there are also provided, a second' slide valve connected betweenthe check valve and the cylinder of the working piston, the cylinder .of' thesecond slide. valve heingin q t i ab uid c mun ation wit th y d the first slide valve; third slide valve which isalso in controllable fluid communication. with the first slide. valve and is also in controllable. fluid communicationwith the second slide valve the second and third slide valves being so arranged thatft'he' slidable elementof each is directly gether, press, against the additional control piston 18 provided with a packing ring, 19 and a second operating head .3a- T as 2.0 ea sfi the a on l t l P s e 18 similarly tothe gasket 6 in the case of piston .4. l

When the working} piston 15 slides over and beyond the port 16 in cylinder'll, a small part of the working air enters a conduit 17 and presses the additional control piston to the left in. cylinder 21a. The gasket 21 is then disengaged by the piston head 18:; and main air flows from thej'con duit 23 to conduits 24' i1d"25 and presses main control piston 4 downwards against a spring 1 2 or against the counter-air. The. gasket 7 is'consequently engaged by the piston 4 to close; the inlet and sket Bis d s n a ed by P 's s d 4 ne ifi b l Th w rk s t n fr n o t e i o 51 ws r m h ndu t mm. new ou l P ovide y t pe f gasket .8 throu h h I cl I1 and is) 1 1. I

During its idle stroke the working piston 15 age pistonrod, is moved a spring' (not illustrated 1'), bythe pressure medium as by means of th ass l-ine 3'5 and chamher 3 6 in Fig. l, by its. own weight or by any otherr'neans into the" de'ad-centre pos'itionpushes the residual air through conduit 10,. aperture of gaskets, and" orifices 11 i'nt'o'the open. Towards the endof' the idle-stroke the working piston 15 resses againsta control" pinpist'on 216, which i's'held pr'essedto the right by a spring 19 and hy the compressed air from the conduit 25'; i As soon as the gasket 28' is disengaged by the piston head 2621,. compressed air" from ilie' spaces above the gasket 5 and fromthe conduits 24 and 25 escapes: into the open through'an orifice 30. Before this: action: occurs;-. the additional control piston- 18 in the conduit 23 is pushed to the right due to the superatmos' pheric' pressure of the pressure medium and 'the gasket (qr-indirectly actuated hythe working piston. In? operatiori; the application offiuid pressure toor the removal fluid pressure fiorn thepisto'n of the first. slide-valve is controlled bysecond and third slide valves;

n brs e t 'at hs vemien' m r lea u d r stood, alternative control. systems arranged", to operate in accordance therewith willnow be describedin greater detail by way of example with reference totlie accompanying drawings in which Figs. 1, 2, 3andj4' are diagrammaticrepresentation. of four such control systems for a unilateral. acting working piston.

Rei'erring to, Fig. l of the. drawings T represents a i M pressure medium. source such as. a compressed air container, connectedlhy. aconduit. through whichthe. compressed. air flows. into. the. cylinder. 3' containing. control gear in the form oflaslide valve,.when. amanually operable pressure varying. control valve 2: is opened cylinder 3. containsta maincontrollpiston-4.having a.packing ring 5 and which serves as a: movable. elementof aninletand outletslide valve in. conjunctionwitlsa-ring whichpreve ntsescape of ain pastthe piston 4 21 seals ifoif. 4 t 'I he' pressure spring. 12,. in cylinder 3; or the" air from line 1, may now" force the main control-piston '4"-upwards with. the result that the outlet. at gasket 8 isv closed and theinlet at gasket. 7' is; opened,-. wherebyanother working cyeleisinitiated. 1 r

The speed 'of the workingpiston- 15 during the'working stroke is: determined-byregula-tirig or adj'u'sting'fthe control-valve. 2 whereas the speedof the working: piston 15 on its return stroke-is re'gulated or adjusted bymeans oi.theadjusting screw 13-whiclirestricts 'or increases the escape of used workin-glair. 7 By providing diiferent-diameter ports or bores lti in the. workingrcylinder 141? is possible.- to vary the stroke fit o t spi m a Fig. 2 illustrates one example of the performance of the invent-ionwherein the port 16: and conduit; 17 of 'Fig. .l have been dispensedwithi' Theworki-rigJs't-roke oi the piston; 15. begins asdescribed in con'ziection with Fig. 1 but towards the end ofthe working? stroke the piston presses immediately against the additional control piston 18,- the disposition" of which" is changed fromthat shown in Fig, 1:. The reversal-ot the main-control piston t 'i's carri d out with; main: air, as. described inconrie'etion with l., i. e.,;.upon movernent of' piston 18 by mainipie ton 15, the main air pressure enters line 24 from line 23, proceeds to cylinder 3, andmoves the control piston 4 to open line to exhaust viaports 11 as previously described- M. M

-By varying the distance of the additionalcontrol piston 18, or of the control pin 26, or of both, 'frorn the working piston 15, the stroke may be made variable. In such a case the conduits 23, 24 are made flexible or provided with ball-and-socket joints.

In Fig. 2 an adjusting member 13' corresponding to adjustment screw 13 in Fig. l' isconnected with the main control piston 4 and can be manipulated with this main control piston either manually or in any other way. Fig. 3 represents a variant wherein the control piston 4 with its piston packing 5 is not only a control means but simultaneously also a working member." The storage tank T for the pressure medium, which as before,

. 18 that is'to say, when, the working piston is required may be compressed air is in communication with the When the control valve 2 is open, the compressedair fills the conduit 23 as well as that portion of cylinder 21a which houses the pressure spring 22 and presses against the additional control piston 18, the lower head 18a of which is sealed on by the gasket 21, and maintains the additional control piston 18 in its rest position, as shown in the drawing. At the same time, however, compressed air flows also through the conduit 10--17 and presses against the packing ring 19 of the additional control piston 18 which is pressed downwards against the pressure of the air issuing from conduit 23 as well as against the spring 22. Air in conduit 101-7 also presses against packing ring 27 of needle valve 26 to close off the bypass orifice 28' in conduit 25. Thus air passes by the gasket 21 which has become disengaged from the piston head 18a, by virtue of the pressure differential between head 18 and head 18a, through the conduit 24 and pushes the main control piston 4, to the right, with the result that the inlet at gasket 7 is closed and the outlet at gasket 8 is opened. In consequence, the air from the conduit 10.17 escapes into the open at 11. Compressed air from conduit 23 and the action of the spring 22 may now push the additional control piston 18 up again where it is once more sealed off by the gasket 21, While at the same time needle valve 26 is returned to its upper position by spring 29.

The spring 12, which has been tensioned during the working stroke of the main control piston 4, now pushes the latter to the left, whereby the air is enabled to escape into the open from the conduits 24 and 25 through the orifices 28', 30. The outlet at gasket 8 is closed and .the inlet at gasket 7 is opened, whereby the same working cycle is repeated periodically. The orifice 28' may be of adjustable nozzle form or a needle valve arrangement as shown may be used and the adjustment of the orifice 30 may be etfected by an adjustable screw. The pressure medium diverted through the orifices 28' and 30 may, if desired, be collected and passed to a container. 1

The speed of the working stroke may be adjusted either by adjusting the control valve 2 and/or by adjusting the orifices 28' and 30. When these orifices are opened up wide, the air escapes at a considerable rate, whereas when they are restricted, the rate of escape of the air is slowed down. In cases where it is found advantageous for the functioning of the apparatus to provide for a slow admission and a fast escape of the control medium towards the additional control piston to remain in its dead-centregosition for a short time after its return strokea doublecting valve 31 on a seat 32 is provided, this valve having a small inlet bore 33 and several larger outlet bores 34. The return of the working piston 15 may again in this case, be effected by a spring 12 as shown, by the pressure medium, by its own weight or in any other way. I

In any of the arrangements described with reference to Figs. 1, 2 or 3 by the provision of a counter-piston 37 which may if desired be sealed off by means of a grooved packing ring the Working piston can be designed so as to make the return stroke of piston 15, also a power stroke. For this purpose a conduit 35 is connected to the conduit 9 and led into a cylinder 36. The pressure medium flows through the conduit 1, the open control valve 2, the con duit 9 in Figs. 1 and 2 and conduit 23 in Fig. 3, past the main control piston 4 (which in the case of Fig. 3 is also the working piston) and the inlet gasket 7, through'conduit 10 and ultimately into the cylinder 14 and moves the working piston 15 through the connecting-link 38 with the smaller counter-piston 37 and the drive coupling member 39 which drives any appropriate device. At the same time the pressure medium from the conduit 9 in Figs. 1 and 2 and conduit 23 in Fig. 3 has also entered the conduit 35 and the second working cylinder 36 where it presses against the counter-piston 37.

After the working piston 15 hascompleted its working stroke it actuates the additional'control piston 18 in Figs. 1 and 2 or opens the gasket outlet 8, 11 in Fig. 3 as already described, whereby the main control'piston 4 is returned, the inlet at gasket 7 being closed and the outlet at gasket 8 being opened. The used working air escapes from the working cylinder 14'through the conduit 10st 11 into the open in Figs. 1 and 2. The pressure medium from the conduits 9 or 23, 35 and the cylinder 36 acts upon the counter-piston 37 and moves the latter with the connecting link 38 and the working piston 15 to the left until one of the reversing members, 26, 18, as shown in Figs.

' l and 2, and needle valve 26, as shown in Fig. 3, comes into action and the reversalof the main piston 4 is brought about. If the working surface of the counter-piston 37 is about half as large as that of the working piston'15, then it is possible to obtain equal working speeds in either direction which can be varied infinitely by means of the control valve 2.

40 and 41 in Figs. 1 through 3 inclusive are restrictions which may act unilaterally 0r bi-laterally, singly or doubly, equally or unequally, and thus control the crosssection of the conduits 10 and 35 in Figs. land 2 or24 and 35 in Fig. 3 accordingly. If, for example, the conduit 35 incorporates a valve-like restriction 40, then the speed of the counter-piston 37 is decelerated towards the end of the stroke and higher pressure is produced in the cylinder 36 than in the cylinder 14. r This compression heats up the pressure medium in the cylinder 36 and the conduit 35 and this effect in compressed-air operation may be desirable, because the heated air is also fed to the control valve 2 which therefore cannot freeze up in the cold. Part of the high pressure produced in the cylinder 36 could be removed from it to be used or stored elsewhere. r Fig. 4 represents a variant without the pipe 35 and wherein the connecting link or rod 38, is provided with a channel 42 with a check valve 43 to enable the storing ofthe working medium in the space 36 for'the return of the piston 37 into its initial position. The working medium flows through the pipe 1, through the open valve 2, the pipe 9, the cylinder 3 of the main control piston 4, the'open ring gasket 7, the pipe 10into the cylinder 14 and moves the working piston 15 with the connecting link or rod 38 and the smaller counterpiston 37 to the right; I In' the deadcenter (or end) position of theworking iStOH'IS-the workingmedium presses through the check valve 43.:andthechanneldl intothe space 36 'where it pushes the counter-piston 3,7 in the opposite direction.

The functional operations of the fluid motor of Fig. 4 remain the same as disclosed with respect to' Fig. l, and all other elemental parts in Fig. 4 are identical'to those shown in Fig. 1. H

By extending the rod. 38 throughthe piston 31 and the cylinder- 36 as by the rod extension 44 it is, for example, possible to operate a single=acting or doubleacting pump 45, a boiler feed. pump or a pneumatic brake pump. v

Alternatively, however, this drive could be taken off the drive connecting member 39; By means of'the member 39 it is possible to operate, for example, a power hacksaw or any other reciprocating machine.

If the reciprocating motion is to be converted into a rotary motion, this can be carried out by means of cranks or a rack-and-pinion mechanism. In the former case a connecting rod with a pin and gear would cooperate with the member 39. member 39 could be designed, for example, as a U- shaped rack or friction bar which drives gears with idling devices and sets them in motion.

Alternatively, the direct connection between the arm member 39 and piston rod 38 may be dispensed with and the rod 38 connected to the driven element 39 by a simple coupling 46.

In any of the constructions of slide valves described, the gaskets may be constituted by grooved rings. When the valve 2 is used to control the supply of compressed air it may be provided with an air bleed passage. In certain applications of the invention, the valve 2 may be dispensed with and the supply and cutting off of the pressure effected by opening, closing or adjusting orifice 30.

In the design of installation embodying the invention, the control valves 2, 4, 18 and 26 together with their related components may be all mounted in a housing. Again, the cylinders 14 and 36 may be assembled together by means of coupling flanges, screws or other means and further all the components 1-45 of the control installation may be assembled to form a unit.

What I claim is:

l. A system for operating a single acting fluid pressure operated motor comprising, a source of fluid pressure, a fluid pressure operated motor including a piston and an enclosing cylinder housing said piston, a plurality of fluid pressure conduits forming communication between said source and said cylinder, a plurality of valves interposed in selectedones of said conduits and including at least one pressure diflerential actuated valve, at least one piston actuated valve projecting into said cylinder, and at least one manually operable variable pressure controlling valve, at least two of said valves being in direct pressure communication with saidmanually operable valve.

2. A system for operating a fluid pressure operated motor comprising, a source of fluid pressure, a fluid pressure operated motor including a piston and an enclosing cylinder housing said piston, a plurality of fluid pressure conduits forming communication between said source and said cylinder, a plurality of valves interposed in selected ones of said conduits and including at least one pressure difierential actuated valve, at least one piston actuating valve projecting into said cylinder, and at least one manually operable variable pressure controlling valve, at least two of said valves being in direct pressure communication with said manually operable valve, said piston including stepped head portions of different diameter, and one of said conduits being connected between said manually operable valve and said motor cylinder in communication with said smaller diameter piston head.

3. The combination as set forth in claim 1 in which said pressure difierential actuated valve is connected in In the latter case the 6 direct pressure communication with said pistonactuated valve through one of saidplurality of conduits. 4 .The combination as set forth in claim 1 in which said plurality of valves. includes a further pressure diflierentialv operated. valve interposed in one of said conduits and. adapted to control admission ofvfluid' pressure mediumv to and. fromsaid. motor cylinder, one of said conduits establishing communication between said further fluid pressure. difierential. operated valve and said one. pressure diflerential operated, valve. 5'. The combination as set forth in claim 1 in which said piston actuated valve includes an. element projecting into said motor cylinder in the path of movement of said piston in one direction.

6. The combination as set forth in claim 1 in which said piston actuated valve comprises a valve sleeve member integral with said cylinder and a valve member integral with said piston.

7. The combination as set forth in claim 1 in which said plurality of conduits includes a first conduit, said manually operated valve member being positioned to control the flow of pressure fluid medium in said first conduit, a second conduit connected between said manually operated valve member and said motor cylinder, a third conduit connected between said manually operated valve member and said cylinder, said one fluid pressure differential operated valve member being interposed in said second conduit and adapted to control the flow of fluid pressure medium therein and resilient means normally biasing said one fluid differential operated valve to a position opening communication in said second conduit between said manually operated valve member and said cylinder.

8. The combination as set forth in claim 2 in which said one conduit includes flow restricting means.

le headed piston, and a resiliently biased check valve positioned in said channel and normally operative to block fluid pressure communication with said smaller diameter piston head.

10. The combination as set forth in claim 2 in which said fluid pressure differential operated valve includes an exhaust port, an inlet port in communication with said manually operable valve, and an outlet port in communication with said cylinder.

ll. The combination as set forth in claim 10 including resilient means normally biasing said fluid pressure differentially operated valve to a position blocking com munication with said exhaust port and opening communication between said inlet and outlet ports.

12. A system for operating a single acting fluid pressure operated motor comprising a source of fluid pressure, a fluid pressure operated motor including a piston, and an enclosing cylinder housing said piston, a plurality of fluid pressure conduits forming communication between said source and said cylinder, a plurality of valves interposed in selected ones of said conduits and including at least onepressure differential actuated valve, and at least one piston actuated valve positioned to project into said cylinder, at least two of said valves being in direct pressure communication with said motor cylinder, said fluid pressure differentially operated valve including a reciprocal valve member having spaced stepped cylindrical portions, a valve chamber enclosing said valve member and including inlet, outlet and exhaust ports, an apertured packing ring positioned in said chamber and dividing the same into spaced fluid pressure tight compartments in co operation with predetermined portions of said valve member.

13. A system for operating a single acting fluid pressure operated motor comprising, a source of fluid pressure, a fluid pressure operated motor including a piston and an enclosing cylinder housing said piston, a plurality of fluid pressure conduits forming communication between said source and said cylinder, a plurality of valves interposed in selected ones of said conduits and including at least one pressure difiterential actuated valve and a manually operable pressure varying valve, said pressure differential actuated valve including a reciprocable 5 valve member and resilient biasing structure for basing said valve member to one limit position whereby communication between said source and cylinder is established, and adjustment means connected with said biasing structure for varying the resilient biasing force whereby 10 the rate of movement of said motor may be adjusted by two separate and independent variables.

- References Cited in the file of this patent UNITED STATES PATENTS Freedman et al Sept. 9, 1952 

